The UN's special envoy for Syria, Staffan de Mistura, says no tangible progress has been made at the final round of Astana peace talks this year.
The UN envoy on Syria said on Thursday there had been "no tangible progress" at talks in Kazakhstan towards a new Syrian constitution, seen as a crucial step towards resolving the country's long conflict.
Staffan de Mistura, who announced his resignation last month, capped his term as peace envoy with two days of talks in the Kazakh capital Astana.
A statement from his office noted the special envoy regretted "no tangible progress in overcoming the 10-month stalemate on the composition of the constitutional committee", following talks sponsored by opposition-backer Turkey and Syrian regime supporters Russia and Iran in Astana.
The meeting in Astana was "a missed opportunity to accelerate the establishment of a credible, balanced and inclusive, Syrian-owned, Syrian-led, UN-facilitated constitutional committee," the statement said.
The two-day negotiations, concluding Thursday, are the 11th in Astana since Moscow began a diplomatic push in early 2017 that effectively sidelined other talks on Syria led by the United Nations.
Syria's grinding civil war has killed more than 360,000 people and displaced millions.